Key information relevant to the recruitment process for the
overall study, such as dates of the recruitment period and locations

No text entered.

Pre-Assignment Details

Significant events and approaches for the overall study
following participant enrollment, but prior to group assignment

20998 participants were enrolled, and 18201 were randomized.

Reporting Groups

Description

Apixaban

Participants received apixaban and warfarin-placebo following randomization during a titration phase using a dosing algorithm for warfarin- placebo; apixaban was dosed at 5 mg twice daily (BID) [or 2.5 mg BID in select subjects]. Subsequent warfarin placebo doses were recommended based upon an algorithm using an encrypted, shammed International Normalized Ratio (INR) procedure to preserve the double blind; however, the final dosing decision rested with the investigator.

Warfarin

Participants received apixaban-placebo and warfarin following randomization during a titration phase using a dosing algorithm for warfarin; apixaban-placebo was dosed at 5 mg twice daily (BID) [or 2.5 mg BID in select subjects]. Subsequent warfarin doses were recommended based upon an algorithm and encrypted INR testing to preserve the double blind; however, the final dosing decision rested with the investigator.

Explanation of how the number of participants for analysis was determined.
Includes whether analysis was per protocol, intention to treat, or another method.
Also provides relevant details such as imputation technique, as appropriate.

Randomized participants

Reporting Groups

Description

Apixaban

Participants received apixaban and warfarin-placebo following randomization during a titration phase using a dosing algorithm for warfarin- placebo; apixaban was dosed at 5 mg twice daily (BID) [or 2.5 mg BID in select subjects]. Subsequent warfarin placebo doses were recommended based upon an algorithm using an encrypted, shammed International Normalized Ratio (INR) procedure to preserve the double blind; however, the final dosing decision rested with the investigator.

Warfarin

Participants received apixaban-placebo and warfarin following randomization during a titration phase using a dosing algorithm for warfarin; apixaban-placebo was dosed at 5 mg twice daily (BID) [or 2.5 mg BID in select subjects]. Subsequent warfarin doses were recommended based upon an algorithm and encrypted INR testing to preserve the double blind; however, the final dosing decision rested with the investigator.

The CHADS2 score is a clinical prediction rule for estimating the risk of stroke in patients with nonrheumatic atrial fibrillation (AF). A high CHADS2 score corresponds to a greater risk of stroke, while a low CHADS2 score corresponds to a lower risk of stroke (range 0 to 6). The CHADS2 score is determined by adding together the points that correspond to the 5 conditions that are present: 1 point each for congestive heart failure, hypertension, age ≥75 years, or diabetes mellitus; 2 points for prior stroke or transient ischemic attack (TIA).

Number of Participants With First Event of Ischemic/Unspecified Stroke, Hemorrhagic Stroke, or Systemic Embolism (SE) During the Intended Treatment Period [ Time Frame: Time to first event in "Intended Treatment Period": started on day of randomization, ended at efficacy cut-off date (date target number of primary efficacy events [448] was expected to have occurred; set to 30-Jan-2011, prior to unblinding). ]

Rate of Adjudicated Stroke or Systemic Embolism (SE) During the Intended Treatment Period [ Time Frame: "Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding). ]

Number of Participants With Event of Major (International Society on Thrombosis and Hemostasis [ISTH]) Bleeding During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Rate of Adjudicated Major (ISTH) Bleed Events During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Number of Participants With Events of All-Cause Death During the Intended Treatment Period [ Time Frame: "Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding). ]

Rate of Adjudicated All-Cause Death During the Intended Treatment Period [ Time Frame: "Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding). ]

Rate of Ischemic or Unspecified Stroke, Hemorrhagic Stroke, Systemic Embolism (SE), and Myocardial Infarction (MI) (as Individual Endpoints) During the Intended Treatment Period [ Time Frame: "Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding). ]

Diagnosis for an acute or evolving MI=elevation of creatine kinase-MB isoenzyme (CK-MB) or Troponin T or I ≥ 2 × the upper limit of normal (ULN), or if no CK-MB or troponin values are available, a total CK ≥ 2×ULN, or new, significant (≥0.04 s) Q waves in ≥2 contiguous leads. For descriptions of Stroke and SE, see Outcome Measure 1.

Time Frame

"Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding).

Safety Issue

No

Population Description

Explanation of how the number of participants for analysis was determined.
Includes whether analysis was per protocol, intention to treat, or another method.
Also provides relevant details such as imputation technique, as appropriate.

Intention to treat analysis, randomized participants. Participants who did not experience an efficacy endpoint event were censored at the earlier of their death date (when death is not part of the endpoint), last contact date, or the efficacy cut-off date (30-Jan-2011). n=number of participants experiencing stated event.

Reporting Groups

Description

Apixaban

Participants received apixaban and warfarin-placebo following randomization during a titration phase using a dosing algorithm for warfarin- placebo; apixaban was dosed at 5 mg twice daily (BID) [or 2.5 mg BID in select subjects]. Subsequent warfarin placebo doses were recommended based upon an algorithm using an encrypted, shammed International Normalized Ratio (INR) procedure to preserve the double blind; however, the final dosing decision rested with the investigator.

Warfarin

Participants received apixaban-placebo and warfarin following randomization during a titration phase using a dosing algorithm for warfarin; apixaban-placebo was dosed at 5 mg twice daily (BID) [or 2.5 mg BID in select subjects]. Subsequent warfarin doses were recommended based upon an algorithm and encrypted INR testing to preserve the double blind; however, the final dosing decision rested with the investigator.

Rate of Ischemic or Unspecified Stroke, Hemorrhagic Stroke, Systemic Embolism (SE), Myocardial Infarction (MI) and All-Cause Death (ACD) (as Composite Endpoints) During the Intended Treatment Period [ Time Frame: "Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding). ]

Number of Warfarin/Vitamin K Antagonist (VKA) Naive Participants With Composite Stroke / Systemic Embolism (SE) / Major Bleeding During the Intended Treatment Period [ Time Frame: "Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding). ]

Rate of Composite Stroke / Systemic Embolism / Major Bleeding in Warfarin/Vitamin K Antagonist (VKA) Naive Participants During the Intended Treatment Period [ Time Frame: "Intended Treatment Period" started on the day of randomization and ended at the efficacy cut-off date (date on which it was expected that the target number of primary efficacy events [448] would have occurred; set to 30-Jan-2011, prior to unblinding). ]

Number of Participants With Events of Major or Clinically Relevant Nonmajor (CRNM) Bleed During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Rate of Events of Major or Clinically Relevant Non-Major (CRNM) Bleed During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Number of Participants With All Bleeding Events During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Rate of All Bleeding Events During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Number of Participants With Adverse Events (AEs), Bleeding AEs, Serious Adverse Events (SAEs), Discontinuations Due to AEs, or Deaths During the Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Rate of Adjudicated Bleeding Endpoints Per Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) During the Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Rate of Adjudicated Bleeding Endpoints Per Thrombolysis in Myocardial Infarction (TIMI) During the Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Number of Participants With Net-Clinical Benefit During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]

Rate of Net-Clinical Benefit During Treatment Period [ Time Frame: "Treatment Period" started with first dose of blinded study drug and ended 2 days after the last dose of blinded study drug. Mean duration of exposure to double-blind study drug was 1.7 years in each treatment group. ]